New HS motor very rough idle

how many teeth on the front and rear sprockets? 9 and 27(inside drive box)

what is the final ratio of your chain sprockets?12 - 1
how many teeth on the drive sprocket and the rear wheel?
not that I don't trust your ratio I just like to figure it out myself
with any changes

tahnks again
 
51 mph lol, it's doubtful it would go that fast

like I was saying not enough reduction in the drive box itself

but

it pulls amazingly well when it engages and even surprises me just because it's all new and not used to it

after tweek runs around the block, lots of them, finally felt safe to go a few miles to the post office

got caught in the rain, totally soaked

on one way street home 30mph limit seems like I might have been going 20 - 25 considering the cars passing the fool riding in the rain with a big grin

was at half throttle I think

sure wish the speedo would work
 
a look inside gearbox

Finally have an inside pic for you. The chain used to be taunt but now
it's drooping a little after a couple hours of riding.

Just put a 56t sprocket on it but will have to wait till tommorrow for test drive.
 

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You could replace that chain, with a better quality chain, which won't stretch so fast.
How about going 1 tooth larger on the driven sprocket?

I'd even consider a ghost sprocket, to take up the slack.
 
getting worse

This tread began with rough idle and still have the problem only it's getting
worse. Have another motor and have been swapping parts so I can say what
is not wrong but there's nothing left in my mind. Hoping for someone to see
the obvious I've missed.

Not only rough idle but missing badly at any speed. In other words it's running
like **** and getting worse.


What it's not:
the spark plug
magneto
carboretor
sheared key on flywheel
valve settings

At idle it races then acts starved and wants to quit then races, over and over.

Inspired??

Please help if you have any ideas.


See the censor edited my word cr@p above.
 
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I had a similar problem with the Hua Sheng 4 stroke. It was fixed by cleaning up the idle jet, and making sure the o ring on the jet was properly in place.

Remove idle screw from the carb.
The small plastic "cap" on the carb body under the idle screw can be lifted with a screwdriver, when you pull it out you will see that it is a jet.
There is a 4mm ID o-ring on the jet. make sure it is in place in the notch.
Give the jet a few sprays with WD-40 to clear it out.
If the o-ring is damaged, I have heard you can get them at Ace Hardware, 4mm ID, 7mm OD or similar.
When you reinstall the jet, make sure it is wet with WD-40 or something so the o-ring doesn't jam up as you push it down.

I will bet that this solves your problem.

My problem was solved by putting the o-ring back in the notch (it was mashed flat) and/or by spraying out the jet.
 
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